The horn fly is a common pest of cattle that causes important economic loses. This hematophagus parasite is distributed throughout much of the tropical and temperate areas of the Western and Eastern Hemispheres. The horn fly was introduced into
We developed a system to produce adult flies in the laboratory using a semisynthetic medium culture. Using this medium we tested the toxic activity of several sporulated B. thuringiensis strains against horn fly larvae. We found one strain with toxic activity. This activity was temperature sensitive indicating that the toxic effect was not produced by a β-exotoxin. Microscopy examination of the sporulated strain showed the presence of bipiramidal paraesporal crystals. Analisys by SDS-PAGE of purified crystals by urografin gradient centrifugation, showed the presence of a unique protein of MW≈130 kDa. At present we are working in the identification of this protein, the cloning of the corresponding gene and the typification of the B. thuringiensis strain.
